Comment: Will 2010 see SSD technology topping out?

Reliability and performance limitations of NAND flash-based SSDs in demanding enterprise applications will be addressed in 2010 by phase-change memory, according to Ed Doller, CTO of Numonyx.

The explosion of data in everything from mobile phones to the enterprise has created an explosion of another sort  low-cost NAND memory. NAND memory started small enough, but over time, it has absorbed just about everything that has been thrown at it. It has grown so much that it is beginning to create new markets and is in fact being used in the most demanding applications  as solid-state drives (SSDs) in big iron enterprise and server farms.
We all read about how SSDs started to take hold in 2009. Companies of all sizes were signing up en masse filled with the excitement over the prospect of lowering their energy bills, among other things. And who wouldn't? The concept of using SSDs instead of hard disk drives (HDDs) to store persistent data is very appealing.

So what aren't they telling us? We'll likely start to find out in 2010.
Don't get me wrong. There is absolute performance and power value in transitioning from HDDs to SSDs. We believe the transition will happen; the issue is that there may not be enough people who are taking a hard look at the technology behind SSDs and asking the tough questions. There is an enormous amount of system-level work going into deploying SSDs, but are we all sure the designs will apply beyond a generation or two?

Reliability concerns

One of the main causes for concern in using SSDs in the enterprise  where the endurance requirements are the highest  comes down to scaling, or how long the technology will reliably perform at the levels and cost you need today and in the future. Remember with any non-volatile floating gate memory device, the more you cycle the device the more failures you tend to observe, and the less data retention you get.

Does the memory device retain the data after hundreds, thousands, or even millions of write cycles? Most of us own multiple devices such as MP3 players and USB memory devices based on NAND flash technology. In normal use, these applications require writing to memory 10, 50, or even 100 times, but never thousands of times. This is the use model that has shaped the technology definition to date.

Ahhh. Let's see whose memory is short and volatile. Mr. Doller is on record claiming that his 45nm (1Gbit) PCM chip would be available by mid 2009:
www.eetimes.com/207001799
It is February 2010 now, and the 1Gbit PCM is not in volume production. Not at all. Can Mr. Doller explain that failure to deliver a commercial 45nm PCM product? The only "commercial" PCM chip is the 128Mbit 90nm disaster formerly known as Alverstone (now Omneo P8P?) which writes at less than 1 megabyte per second, that is, 2x slower than Numonyx's own NOR and up to 15x slower than NAND. So, no, nobody in their right mind would use PCM in SSDs, even when costs per gigabyte are ignored. Those costs, by the way, appear to be about $200 per gigabyte for the Omneo P8P, or 100x as expensive as NAND, and about $60 per gigabyte for the "upcoming" 45nm part, 30x as expensive as NAND, assuming that 45nm part ever gets delivered in volume, based on a chart from a recent Numonyx presentation.
Just watch this webcast and calculate the horrible write speed yourself:
event.on24.com/r.htm?e=183505&s=1&k=7BCF2A67876DA214BFF6D18937E47D44
In the mean time, Fusion-io has been delivering for months a reliable NAND-based non-volatile "SSD" that writes at 1.4 gigabytes per second and reads at 1.5 gigabytes per second. And, yes, it is perfect for the enterprise. Unlike the PCM, which has been promised since 1970s, but never arrived.